Malaria and Rome: A History of Malaria in Ancient Italy (24 page)

⁸ Herlihy and Klapisch-Zaber (1985).

⁹ Carmichael (1989) on mortality patterns in late medieval Florence.

¹⁰ Shaw (1996: 132).

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Demography of malaria

outbreaks of epidemic typhus in Burundi in Africa and in Russia.¹¹

Similarly Shaw noted the gradual disappearance of the excess summer mortality in Italy from the 1860s to the 1960s, but did not notice the almost exact correlation of this trend with the gradual eradication of malaria. In contrast Brown found a very strong statistical correlation between mortality trends in Sardinia and malaria eradication over the very same hundred-year period.¹² Del Panta observed that ‘the official statistics can only reveal, however, the phase in which mortality from malaria was declining, starting in 1887’. The data for causes of death upon which Shaw relied postdate
the beginning of the demographic transition towards the modern low-mortality and low-fertility demographic regime in Italy. Consequently these data are of limited value for the pre-modern period. Del Panta stated that the transition towards the modern low mortality demographic regime commenced in Tuscany in the period 1875–80.¹³

The second lesson to be drawn from examining Shaw’s use of national statistics is that in demography
all valid studies must commence at the local level
, with, for example, the sort of parish studies which formed the foundation for the monumental population history of England by Wrigley and Schofield. The failure to appreciate the importance of local variation in demography, such as the differences between Grosseto and Treppio noted at the beginning of this book (see also Ch. 5. 4 below), is the single biggest deficiency of the bulk of research in ancient Roman demography carried out over the last thirty years or so. One of the main conclusions reached in this book is that it is in fact impossible to generalize about the demography of a region as small as central Italy in antiquity, never mind the whole Roman Empire.

There is a second very important reason why the national statistics for mortality in 1887–9 in Italy are an unreliable guide to the likely impact of malaria on mortality patterns in antiquity. As a specialist in malariology put it, ‘reporting of deaths by cause has been of limited use for the investigation of the impact of malaria and its control on mortality’.¹⁴ The reason for the unreliability of ¹¹ Raoult
et al
. (1998) and Tarasevich
et al
. (1998) on typhus.

¹² Shaw (1996: 112); Brown (1986: 857).

¹³ Del Panta
et al.
(1996: 292 n. 10):
le statistiche ufficiali possono cogliere, purtroppo, solo la fase dis-cendente della mortalità per malaria, a partire dal 1887
; del Panta
et al.
(1996: 152); Sori (1984: 542–3).

¹⁴ L. Molineaux in Wernsdorfer and McGregor (1988, vol. 2, p. 974).

Demography of malaria

119

national statistics is that ‘medical science shows that for each death attributed to malaria there are several other deaths, which are attributed to other causes, but nevertheless are directly linked to malaria or indirectly caused by the debilitating effects of malaria infections’.¹⁵ The empirical demographic evidence for this conclusion is that it has frequently been observed, both in Italy in the past and in tropical countries today, that after the eradication of malaria the reduction in
total
mortality rates is much larger than the reduction that would have been predicted from the proportion of deaths that were directly attributed to malaria before its eradication. For example, Hackett described the town of Sermoneta on the edge of the Pontine Marshes in 1925, just before eradication started. The population of Sermoneta, which could not reproduce itself, had a crude death rate of 41 per 1,000. All the children had splenomegaly, but only a dozen individuals, mainly children, had acute symptoms of malaria, because almost all adults had developed acquired immunity earlier in life. Only 8% of all deaths were directly attributed to malaria in 1925 (in absolute numbers, three out of thirty-seven). Nevertheless the eradication of malaria in Sermoneta led to a fall in the crude death rate from 41 per 1,000 to 20 per 1,000.¹⁶

Although the problems of Sermoneta in the early twentieth century were a product of the early modern period, there is no doubt that other communities in western central Italy were affected in the same way much earlier. For example, Toubert quoted the decree of Pope Innocent IV in  1253 granting permission to the inhabitants of Mozzano to move their village to a new location, because of ‘bad air’ in summer. This text clearly describes virtually the entire population of Mozzano in the thirteenth century as severely affected by malaria, and shows malaria directly altering human settlement patterns in that period. (Since the town had been built in a place that was so pestilential and unhealthy, owing to bad air, especially in summer, almost all of its inhabitants suffer from severe disease and chronic lethargy . . . we shall allow them to move to the place called Colle Vecchio to live in the territory of the town set aside for them there).¹⁷

¹⁵ Bonelli (1966: 662):
la scienza medica mostra che per ogni morto classificato come deceduto a causa della malaria ce ne sono parecchi altri classificati come morti per ‘altri’ eventi morbosi, i quali, peraltro, sono alla malaria direttamente connessi o indirettamente dovuti al processo di debilitazione fisica delle persone col-pite
.

¹⁶ Hackett (1937: 237); Molineaux (1997); Brown (1986); Giglioli (1972).

¹⁷ Toubert (1973: i. 363–4 n. 3):
cum castrum in tam pestifero et corrupto sit loco constructum quod

120

Demography of malaria

19. A view of Sermoneta, a hill town dominated by the Castello Caetani, with a history of contact with malaria. The following saying, quoted from the guidebook,
Sermoneta: storia del paese
(1989) by L. Sciotti and A. Nastri, refers to malaria:
Sermoneta che stai ncima a na fossa, | ntorno ntorno ci sta l’acqua puzza:| a le femmene fa cresce la trippozza, | a gli ommeni ce cala la cocozza
.

When malaria eradication caused
a reduction in overall mortality of more than 50%
, as it did in Sermoneta, it seems reasonable to conclude that malaria did in fact dominate the mortality regime before propter aeris intemperiem, aestivo praecipue tempore, habitatores ipsius quasi omnes infirmitates graves et diutinos languores incurrunt . . . transferendi se ad locum qui Collis Vetulus
[modern Collevecchio]
nun-cupatur . . . in territorio castri predicti ad inhabitandum inibi . . . concedere curaremus
.

Demography of malaria

121

eradication, even if the bulk of its effects were indirect rather than direct. In tropical countries similar results followed the eradication of malaria. One study estimated that in Ceylon the total number of deaths in which malaria played a role was 4.7 times that of the deaths caused directly by malaria, while in the coastal regions of British Guyana the total number of deaths involving malaria was 3.8 times that of those directly attributed to it.¹⁸ The standard view of malariologists is that ‘the mortality attributable to malaria . . .

was about three times the mortality actually attributed to malaria on the basis of death certification’.¹⁹ For Grosseto, for example, where 23% of all deaths were directly attributed to malaria in 1882, that would imply that well over half of all deaths were in fact linked to malaria, directly or indirectly. Morbidity data, which were collected alongside the cause-of-death data for Grosseto in 1840–41, indicate that about 60% of all recorded illnesses in Grosseto were intermittent fevers.²⁰ This suggests that malaria might have been more frequent in Grosseto than all other diseases put together.²¹ In such contexts, it is easy to understand the equation of ‘fever’, puretÎß or
febris
, with malaria as the disease
par excellence
, as seen for example in the
de medicina
of Celsus. Malaria was the first disease discussed by Celsus in book 3 of his work, when he considered diseases one by one. He explicitly stated that malarial fevers were extremely common, for the benefit of any modern historians who find it hard to believe:

The next subject is the treatment of fevers, which both affect the entire body and are extremely common. One type of fever is quotidian, the second tertian, and the third quartan.²²

The data from Grosseto demonstrate the scale of the effect which malaria might be expected to have had on the population of at least some parts of the city of Rome in Galen’s time, when it was endemic (see Ch. 8 below). Since the indirect effects of malaria ¹⁸ Newman (1965: 76–9, 158–60). See most recently Jones (2000).

¹⁹ L. Molineaux in Wernsdorfer and McGregor (1988: ii. 976).

²⁰ Del Panta (1989: 48–9 n. 23). He stated that the effects of malaria were largely indirect as far as adult mortality in Grosseto was concerned. C. Fermi estimated that malaria was implicated in over 50% of all deaths in Sardinia as recently as 1900 (Brown (1986) ).

²¹ Similarly Desowitz (1997: 195) cited a report from the United States Public Health Service in 1919 which concluded that in the southern states of the USA malaria was more important than tuberculosis, typhoid fever, dysentery, and pellagra put together.

²² Celsus 3.3.1:
sequitur vero curatio febrium, quod et in toto corpore et vulgare maxime morbi genus est.

Ex his una cotidiana, altera tertiana, altera quartana est
.

122

Demography of malaria

are so important, indirect methods for estimating its effects on mortality, such as comparisons of overall mortality levels (most simply by crude death rates) or of the age-structures of populations (as between Grosseto and Treppio) are in fact a better guide than direct methods, such as the Italian national statistics for causes of death used by Shaw. Indirect methods are the chosen methods of professional malariologists.²³

In view of the quantitative importance of malaria in some areas, as shown by the data from Grosseto, it is not surprising that the popular explanations for malaria were sometimes transferred to other diseases, for want of anything better, but this only serves to demonstrate the all-pervasive influence of malaria in those areas where it occurred. Undoubtedly this also happened in antiquity, but the best example is the great epidemic of syphilis which swept across Europe in the years immediately following the return of Columbus from the New World. Leoniceno, in a booklet produced as part of the dispute at the court of Ferrara in  1497 concerning the nature of the epidemic, carefully discussed the types of diseases mentioned by classical authors and correctly concluded that the (for some) new disease was quite distinct from the
elephantiasis
or leprosy described in antiquity. Nevertheless he was unable to resist explaining it in Hippocratic terms and associating it with the massive Tiber flood in December 1495, even though he observed that the whole of Italy experienced very high rainfall in that particular year.²⁴ Similarly Fracastoro, in his poem on syphilis which gave the disease its modern name, advised people to avoid the ‘bad air’ of marshes and south winds:

First of all I would urge you not to be familiar with all types of air: avoid ²³ Dobson (1997: 134) on the use of crude death rates; L. Molineaux in Wernsdorfer and McGregor (1988: ii. 974).

²⁴ Leoniceno (1497) added two extra verses to the tetrastichon, which had been composed by another poet about the Tiber flood in 1495, to emphasize the high rainfall all over Europe in that winter:
Tempore Alexandri sexti nonisq; decembris
|
Intumuit thybris bis senas circiter ulnas.
|

Insula quaeque domus facta est. mediisque repente
|
Circunducta viis aequabat cymba fenestras.
|
Deucalion eo vix tantum tempore tellus
|
Diluvium passa est, latuit cum tota subundis
. ((In the time of Pope Alexander VI, on the 5th of December, | the Tiber rose about a dozen arm-lengths | Each house became an island, and suddenly in the middle | of the streets a boat brought around reached the height of the windows. | Scarcely so much land was flooded at the time when Deucalion survived a flood that submerged everything.) On Leoniceno and the medical dispute at Ferrara see Arrizabalaga
et al
. (1997: 59–66, 72–7, also 195–6 on the various epidemics in Rome in the sixteenth century).

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123

winds which always blow from the south, since they are loaded with dirt and the humidity of foul marshes.²⁵

Since syphilis occurred in many parts of Europe which had no marshes, no ‘bad air’, no sirocco wind, and no river Tiber, the environmental aspects of malaria are obviously of no value at all for explaining syphilis. It is testimony to the enormous influence of malaria that ideas for explaining it were transferred so readily to other, utterly dissimilar, diseases, like syphilis. However, malaria did not only interact with other diseases in the human mind at the level of ideas concerning disease causation. The various pathogens also interacted in reality.

5.2 I      